Refrigerating apparatus



April 12, 1938. v. w. SMITH REFRIGERATING APPARATUS Filed April 5, 19557 W INVENTOR.

ATTORNEYS Patented Apr. 1938 UNITED STATES REFRIGERATING APPARATUSVictor W. Smith, Dayton, Ohio, assignor toGen- -eral Motors Corporation,Dayton, Ohio, a corporation of Delaware Application April 5, 1935,Serial No. 14,76

2 Claims.

This invention relates to refrigerating apparatus and more particularlyto heat interchangers therefor.

Recently more extensive use has been made of heat interchangers forrefrigerating systems wherein the heat present in the liquid beingsupplied to the evaporating means is transferred to and absorbed by thecold vapor which is discharged from the evaporating means and is returned to the compressor or liquefying means. In these heatinterchangers the liquid contacts one side of a metal wall while thecold gas contacts the other side. This on its face would seem to providegood heat transfer between the warm liquid refrigerant and the coldevaporated refrigerant but unless a very great amount of metal surfaceis extended into the path of the cold gas, the gas does not absorb asubstantial amount of its capacity. for absorbing heat from the liquidsince there is not suflicient intimate contact of the gas with themetal; wall.

It is an object of my invention to provide a refrigerating system withan improved heat exchange device in which substantially the entire heatabsorbing capacity of the evaporated refrigerant is employed to absorbthe heat of the warm liquid refrigerant.

It is another object of my invention to provide an improved heatexchange device for a refrigerating system wherein the cold evaporatedrefrigerant is brought into intimate contact with a heat conductor inheat exchange relation with the liquid refrigerant.

It is a further object of my invention to provide a heat interchangerfor a refrigerating system wherein the cold evaporated refrigerant isbubbled through a liquid which transfers the heat from the liquidrefrigerant to the cold evaporated refrigerant.

Further objects and advantages of the present invention will be,apparent from the following description, reference being had to theaccompanying drawing, wherein a preferred form of the present inventionis clearly shown.

"In the drawing:

The figure is a diagrammatic representation of a refrigerating systemembodying my invention.

In the form of my invention disclosed herein, a refrigerant liquefyingapparatus is provided which supplies liquid refrigerant to anevaporating means which evaporates the liquid refrigerant and forms acold gas which is bubbled through a heat exchange liquid on'its returnto the liquefying means. This heat exchange liquid is in contact withthe conduit through which the liquid refrigerant extends in conductingthe liquid refrigerant from the liquefying means to the evaporatingmeans. The heat transfer liquid conducts the heat from the warm liquidrefrigerant to the cold gaseous refrigerant which absorbs the heat whenit is bubbled through the heat transfer liquid.

Referring now to the drawing, there is shown a refrigerant liquefyingapparatus generally designated by the reference character 20 whichincludes a compressor 22 driven by an electric motor 24 for compressingthe refrigerant and for forwarding the compressed refrigerant to acondenser 26 where the compressed refrigerant is liquefied and collectedin a receiver 28. From the receiver 28 the warm liquid refrigerant isconducted through a supply conduit 30 to a thermostatic expansion valve32 located within an insulated compartment 34. The thermostaticexpansion valve 32 controls the flow of liquid refrigerant to arefrigerant evaporating means 36 also located within the compartment 34.The liquid refrigerant evaporates within the evaporating means 36 underreduced pressure and absorbs heat from the compartment 34.

The evaporated refrigerant is approximately the evaporator temperaturewhen it leaves the evaporator. In its return' to the compressor itnormally becomes heated by the surrounding air. and by the com n'essoritself so that its capacity so for absorbing heat is thereby wasted to aconsiderable extent. However, if this capacity for absorbing heat isused in cooling the warm liquid refrigerant which is supplied to theevaporating means, the efficiency of the system would be 111- creasedsince less refrigerant would be required to be evaporated in order toreduce the temperature of the liquid refrigerant to the temperature ofthe evaporating means 36. Heretofore it has been customary when desiredto secure greater efllciency to provide a heat exchange member having acommon wall which is contacted on one sideby the liquid refrigerantandby the cold gaseous refrigerant on the other side. This would cause thetemperature of the liquid refrigerant 45 to be reduced by the amount ofheat which was withdrawn through the metal dividing wall by the coldevaporated refrigerant. Such heat exchangers recovered some of thecapacity for absorbing heat of the cold evaporated refrigerant butinasmuch as the cold evaporated refrigerant did not come into intimatecontact with the liquid refrigerant or in intimate contact with themetal wall separating the liquid and gaseous refrigerant,

a considerable portion of the heat absorbing ca- 55 pacity of the coldevaporated refrigerant was not used.

I, by my invention have improved this heat transfer and usesubstantially the entire heat absorbing capacity of the cold evaporatedrefrigerant. In order to do this, I provide a metal container 38 withinthe insulated compartment 34 which contains a heat tranfer liquid 40preferably having a high capacity for transferring heat such as mercurywhich is immiscible with the refrigerant in the system. Instead ofmercury, other liquids such as the same oil which is used to lubricatethe compressor may be used as the heat transfer liquid. The coldevaporated refrigerant is conducted by the conduit 42 to the lowerportion of the container 3d. The cold evaporated refrigerant bubblesthrough this heat transfer liquid and collects in the top of thecontainer '38 above the liquid level. A second return conduit 46connects to the top of the container 38 for returning the evaporatedrefrigerant which collects in the top of the container to the compressor22. The supply conduit 3t) extends through the container 38 and has acoiled portion 46 submerged within the heat transfer liquid.

The heat from the liquid refrigerant thus passes through the walls ofthe coiled portion of the supply conduit and then transfers the heat tothe heat transfer liquid at which in turn transfers the heat to the coldevaporated refrigerant which bubbles through the heat transfer liquid46. The size of the bubbles may be controlled by the size of the outletof the conduit 42 within the container 38 and preferably a plurality ofsmall outlets maybe provided for the conduit 42 in the lower portion ofthe container 38 in order to provide very intimate contact between thegas and the liquid. Should any lubricant collect upon the surface of theheat transfer liquid, it will be returned to the compressor by theevaporated refrigerant which will bubble through the layer of lubricantand pick up some of the oil.

The operation of the system may be controlled by any suitable means suchas by the temperature of the evaporating means 36, by the temperature ofthe compartment 34, or as shown by the pressure within the returnconduit 44. In the control as shown there is provided a pressureoperated snap acting means 50 which is connected and operated by thepressure in the return conduit 44 for controlling the supply of electricenergy to the electric motor 24.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form. it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. A refrigerating apparatus comprising, a

cooling element, a circulating unit and a plu= rality of conduitsconnecting same together to form a closed system, a. working fluidwithin said closed system and adapted to be circulated therethrough bysaid circulating unit through one of said conduits to said coolingelement and from said cooling element to said circulating unit throughthe other of said conduits, said closed system including a heatexchanger comprising a receptacle containing a heat transfer fluid, aportion of said conduit which conveys working fluid from saidcirculating unit to said cooling element extending in heat exchangerelation with said heat transfer fluid in said heat exchanger, and saidconduit which conveys working fluid from said cooling element to saidcirculating unit being arranged to cause the working fluid to bubbledirectly through the heat transfer fluid withinthe receptacle during itsreturn flow to said circulating means, said heat transfer fluid beinginert with respect to said working fluid whereby the heat transfer fluidis retained in the receptacle while said circulating unit is circulatingthe working fluid therethrough.

2. A refrigerating apparatus comprising, a cooling element, arefrigerant compressing and circulating unit, a condenser and aplurality of conduits connecting same together to form a closed system,a refrigerant medium within said closed system adapted to be circulatedtherethrough by said compressing and circulating unit through one ofsaid conduits to said cooling element and from said cooling element tosaid compressing and circulating unit through another of said conduits,means interposed in said .one of said conduits between said condenserand said cooling element for controlling the flow of the circulatedrefrigerating medium to the cooling element, said closed system alsoincluding a heat exchanger separate from said cooling element andcomprising a receptacle containing a heat transfer fluid, the receptacleof said heat exchanger being in intimate heat transfer relation withthat portion of said another of said conduits extending between saidcondenser and said refrigerant flow control means, and said one of saidconduits which conveys the refrigerant medium from said cooling elementto said compressing and circulating unit being arranged to cause therefrigerating medium to bubble directly through the heat transfer fluidwithin the receptacle dm-ing its return flow to said compressing andcirculating unit, said heat transfer fluid being inert with respect tosaid refrigerating medium whereby the heat transfer fluid is retained inthe receptacle while said compressing and circulating unit iscirculating refrigerant therethrough.

VICTOR W. SMITH.

